Bodies for many vehicles typically include numerous structural and non-structural panels joined together to form a self-supporting, unitary, structural shell known as a uni-body. The uni-body eliminates the need for having a separate structural frame extending the length of the vehicle, as is required in traditional body-on-frame construction for vehicles, such as trucks. Generally, the uni-body panels include a front end, a cowl, a floor pan, a bulkhead, a trunk, and a roof, or hard top. Many uni-body vehicles include a front structural assembly and a rear structural assembly to facilitate affixing the body to the front and rear suspensions, respectively. These structural assemblies may include tubular members perimeter welded to the panels, or may be plates or additional panels formed as webs or reinforcement portions where a suspension portion is attached.
In many uni-body vehicles, the front end includes an engine compartment that partially encloses the engine. The front end is generally strengthened by the front suspension components in a lower portion, but experiences deflection due, at least in part, to the attachment of the front suspension to upper portions, such as shock towers. Many vehicles do not include any components to structurally stiffen and strengthen the front end, especially at upper portions of the shock towers.
Uni-body construction is well suited to a vehicle having a hard-top roof structure, such as a sedan or a coupe. In such a vehicle, the roof provides a portion of the structural strength and stiffness of the uni-body that is required for joining the engine and suspension components at the front of the vehicle to the rear suspension.
In vehicles such as convertibles or roadsters, however, having a soft-top or no top, or in vehicles where a significant portion of the top is removable, the remaining portion of the uni-body must include sufficient additional structure to provide a uni-body that is strong enough and stiff enough to withstand the static and dynamic loads incident with operation of the vehicle. In such vehicles, the number and material gage of the individual components of the uni-body must often be more than doubled in some areas to achieve the required structural strength and stiffness of the uni-body. Adding these components, and increasing the material thickness, undesirably increases the cost, weight and complexity of the uni-body of the vehicle, and can require that the assembly procedures on an assembly line be altered considerably for accommodating vehicles without hard-top roof structures.
Current body production methods may benefit from an improved architecture and method for producing a uni-body, providing the additional structural strength and stiffness required in certain types of vehicles, such as convertibles, roadsters, and vehicles where a significant portion of an otherwise hard-top roof are removable, that can be assembled on a conventional uni-body assembly line with common manufacturing techniques.